80 lb Concrete Bag Coverage: 0.60 ft3, 1.8 sq ft
Answer first: one 80 lb concrete bag yields 0.60 ft3, 1,037 cu in, or 0.022 yd3, covers 1.8 sq ft at 4 in, and 30 sq ft needs 19 bags.
Quick answer
0.60 ft3 / 1.8 sq ft
1,037 cu in; 30 sq ft needs 19 bags and 100 sq ft needs 62 bags with waste
Answer first: one 80 lb concrete bag commonly yields about 0.60 ft3 of mixed concrete, or about 1,037 cubic inches and 0.022 yd3. At 4 inches thick, that same bag covers about 1.8 sq ft before waste. A 30 sq ft pad at 4 inches needs 17 bags before waste or 19 bags with 10% waste. A 100 sq ft slab at 4 inches needs about 62 bags with waste.
Use the Concrete Bag Calculator when you need final whole-bag rounding from length, width, thickness, waste, and bag price. Use this coverage chart when the question is specifically how far one 80 lb bag goes at 2, 3, 4, 5, or 6 inches.
Search answer map for 80 lb bag coverage
Use this map when the search wording is about coverage, volume, square feet, or the 30 sq ft checkout case.
| Search wording | Direct answer | Decision check |
|---|---|---|
| 80 lb bag concrete coverage volume | 0.60 ft3 | Mixed yield, not package size. Confirm the printed yield. |
| How many cubic inches does an 80 lb concrete bag cover? | 1,037 cu in | 0.60 x 1,728; useful for odd unit searches. |
| 80 lb bag in cubic yards | 0.022 yd3 | 0.60 / 27; about 45 bags per yd3 before waste. |
| 80 lb concrete bag is how many sq ft? | 1.8 sq ft at 4 in | Area changes with thickness. Use the table below. |
| How much area does an 80 lb bag cover for 30 sq ft? | 19 bags with 10% waste | About 1,520 lb dry mix to handle. |
| 100 sq ft at 4 in | 62 bags with 10% waste | Pallet-plus order; compare ready-mix. |
The main mistake is treating coverage as a final shopping list. Coverage is only the first conversion. The buying decision also needs waste, whole-bag rounding, dry weight, pallet count, pickup payload, mixer pace, and a ready-mix or delivery comparison.
Coverage by thickness
These values use the common 0.60 ft3 planning yield for an 80 lb bag.
| Slab thickness | One 80 lb bag covers | 30 sq ft before waste | 30 sq ft with 10% waste | 100 sq ft with 10% waste |
|---|---|---|---|---|
| 2 in | about 3.6 sq ft | 9 bags | 10 bags | 31 bags |
| 3 in | about 2.4 sq ft | 13 bags | 14 bags | 46 bags |
| 4 in | about 1.8 sq ft | 17 bags | 19 bags | 62 bags |
| 5 in | about 1.4 sq ft | 21 bags | 23 bags | 77 bags |
| 6 in | about 1.2 sq ft | 25 bags | 28 bags | 92 bags |
If your slab is thinner than 4 inches, one bag covers more square feet. If it is thicker than 4 inches, one bag covers less. Structural thickness, frost, subgrade, reinforcement, drainage, and permits should still be checked locally.
Formula
coverage sq ft = 0.60 / (thickness inches / 12)
At 4 inches:
coverage sq ft = 0.60 / (4 / 12)
coverage sq ft = 1.8
For bag count:
bags before waste = total sq ft / coverage sq ft
bags to buy = round up(bags before waste x 1.10)
For a 30 sq ft pad at 4 inches:
30 / 1.8 = 16.7 bags
round up to 17 bags before waste
17 x 1.10 = 18.7, so buy 19 bags
80 lb coverage turns into a buying decision
The square-foot answer is only useful if it leads to a realistic buying plan. Use these thresholds before putting bags in a cart.
| Project answer | Bags to buy | Dry mix to handle | Buying signal |
|---|---|---|---|
| 30 sq ft at 4 in = 19 bags with waste | 19 | 1,520 lb | Usually still a bag job, but check vehicle payload. |
| One common 42-bag pallet | 42 | 3,360 lb | About 0.93 yd3 before waste and roughly 70 sq ft at 4 in after waste. |
| 100 sq ft at 4 in = 62 bags with waste | 62 | 4,960 lb | Pallet-plus order; price store delivery and ready-mix. |
If your answer is close to one pallet, build a shopping list before buying. If it is over one pallet, get at least one ready-mix or mini-mix quote so shelf price does not hide delivery, lifting, mixer pace, or finish-time risk.
Coverage vs volume
Some searches ask for coverage and some ask for volume. They are related but not interchangeable.
| Query wording | Answer | Use this when... |
|---|---|---|
| 80 lb bag concrete coverage volume | 0.60 ft3 | You need the mixed yield. |
| 80 lb concrete bag cubic inches | 1,037 cu in | The question uses inches or odd units. |
| 80 lb bag in cubic yards | 0.022 yd3 | You are comparing bags with ready-mix. |
| 80 lb bag square feet at 4 in | 1.8 sq ft | You know the slab thickness. |
| How many 80 lb bags per yard? | 45 before waste | Use 50 bags as a 10% waste shopping check. |
If someone asks how many feet an 80 lb bag covers, the missing word is usually square feet and the missing input is thickness. Without thickness, an area answer is incomplete.
Common project checks
These examples use 4 inch thickness and 10% waste.
| Project size | Concrete volume with waste | 80 lb bags | Practical note |
|---|---|---|---|
| 4x4 slab | 0.22 yd3 | 10 bags | Small repair or pad. |
| 6x6 slab | 0.49 yd3 | 22 bags | Still usually practical as bagged concrete. |
| 8x8 slab | 0.87 yd3 | 40 bags | Check pickup payload and mixer pace. |
| 10x10 slab | 1.36 yd3 | 62 bags | Pallet-plus signal; compare ready-mix. |
| 12x12 slab | 1.96 yd3 | 88 bags | Usually a ready-mix or crew-planning decision. |
For exact slab-size answers, compare Concrete Bags for a 6x6 Slab, Concrete Bags for an 8x8 Slab, and How Much Does a 12x12 Concrete Slab Cost?.
Pallet and ready-mix warning
A common 80 lb pallet is often planned as 42 bags, or about 3,360 lb of dry mix. At 0.60 ft3 per bag, that pallet yields about 25.2 ft3, or about 0.93 yd3 before waste.
At 4 inches thick, that is about 76 sq ft before waste. After a normal waste allowance, one pallet is closer to a 70 sq ft planning screen. If your answer is one pallet or more, compare:
- store delivery fee;
- pickup payload and unloading;
- mixer rental or mixing crew;
- finishing time before the concrete starts setting;
- ready-mix minimum order or short-load fee.
Use the Concrete Bag Pallet Weight Guide, Ready-Mix vs Bags Calculator, and Concrete Quote Reviewer before buying pallet-scale 80 lb bags.
Sources and checks
This chart is a planning worksheet, not a product warranty or structural design. Exact yield can vary by product line, region, aggregate, moisture, and label.
| Check | Source | How it is used |
|---|---|---|
| Bag yield and coverage | QUIKRETE calculator and Sakrete concrete calculators | Cross-checks the common 0.60 ft3 80 lb yield and slab coverage math. |
| Ready-mix and yield caution | NRMCA CIP 31: Ordering Ready Mixed Concrete and NRMCA CIP 8: Discrepancies in Yield | Keeps bag coverage tied to waste, yield checks, and ready-mix comparison. |
| Broad bag chart | Concrete Bag Coverage Calculator | Compares 40 lb, 60 lb, and 80 lb bag coverage in one place. |
Concrete Estimator Hub is independent and is not affiliated with these manufacturers, retailers, or suppliers.
FAQ
How much does an 80 lb bag cover at 4 inches?
About 1.8 sq ft before waste, using a common 0.60 ft3 mixed yield.
How much does an 80 lb bag cover at 3 inches?
About 2.4 sq ft before waste.
How much does an 80 lb bag cover at 6 inches?
About 1.2 sq ft before waste.
How many 80 lb bags cover 30 sq ft at 4 inches?
About 17 bags before waste, or 19 bags with 10% waste.
How many 80 lb bags cover 100 sq ft at 4 inches?
About 56 bags before waste, or 62 bags with 10% waste.
Should I use 80 lb bags for a large slab?
Maybe, but once the count reaches a pallet or a full cubic yard, check ready-mix delivery, short-load fees, pickup payload, mixer time, and labor pace before buying dry mix.
Next step
Use this chart as the fast 80 lb coverage answer. Then run the actual project through the Concrete Bag Calculator, turn the result into a Concrete Material Shopping List, and compare pallet-scale orders with the Ready-Mix vs Bags Calculator.
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Publishers, contractors, DIY blogs, and home improvement guides may cite this page when a concrete calculator, bag count estimate, or planning chart helps their readers.
Quote planning next step
Turn this guide into a concrete buying check
Run the matching calculator, then compare ready-mix, bagged concrete, delivery fees, access needs, and quote gaps before you buy materials or approve a contractor number.